Engines, transmissions and geared mechanisms start and operate begrudgingly if at all in certain cold environments due to a variety of factors. These include the increased viscosity achieved by the oil associated with the components as a result of the low temperature, poor gear and bearing fit, and poor vaporization of fuel. For example, automotive and aircraft engines can be difficult to start in cold weather, and at the same time the associated transmission gears and differentials are sluggish until they warm up. Upon temperature decline, gear cases contract at a greater rate than the gears. Gears carrying shafts that ride on bearings contract less than the bearings, which can result in binding.
Various heaters have been devised in order to preheat the oil and associated mechanical components preparatory to operation. Such devices include electric emersion heaters for oil sumps and reservoirs, electrically heated connecting bolts, bond-on pad type electric heaters, and thermocouple well heaters.
The mechanical components under consideration are frequently contained in a housing that is either forged, stamped or cast. The housing comes apart at parting surfaces which require the use of a gasket when assembled in order to check fluid leak. Some of these housings are frequently routinely disassembled for maintenance. An example of this is the rocker cover of an aircraft cylinder head. A new gasket is required for each reassembly. Other such housings have exactly matching surfaces and are disassembled infrequently. Examples of this include the turbofan engine inlet to fan housing, and the snowmobile carburetor to cylinder head connection.
An approach to this problem is shown in U.S. Pat. No. 2,680,185 to Basile. That patent discloses a gasket heater for disposition between the cylinder block and cylinder head of an internal combustion engine. The gasket comprises a cork or cork like body encased in a sheet of thin deformable sheet material. A heater wire is embedded in the cork body. The cork presents an unsatisfactory material for embedding the heater due to its inability to withstand high temperatures.